A fuel cell stack is an electricity-generating device producing electrical energy through an electrochemical reaction between hydrogen and oxygen by fuel cells, and may be applied to fuel cell vehicles, for example.
A fuel cell stack may be configured as an electricity-generating assembly in which hundreds of units of fuel cells are successively arranged. The fuel cells each have a configuration in which separators are disposed on opposing sides with a membrane-electrode assembly interposed therebetween. Fuel cells, in a state of being pressed at a predetermined pressure, are fastened through an end plate and a fastening unit.
The MEA includes an electrolyte membrane and a cathode catalytic layer and an anode catalytic layer formed on opposing sides of the electrolyte membrane. A gas diffusion layer (GDL), a gasket, and the like, are stacked on the catalytic layers. The separators each have a flow channel allowing a reaction gas of hydrogen and air to flow to the anode catalytic layer and the cathode catalytic layer.
In the fuel cell stack, since hundreds of units of fuel cells are stacked and pressed, airtightness of the fuel cells may be defective due to various reasons. An airtightness-defective cell causes a reaction gas to flow out to degrade efficiency and performance of the fuel cell stack and causes a safety problem. Thus, testing an airtightness defect of fuel cells is essential in a process of assembling a fuel cell stack.
In the related art, airtightness testing is performed in a state in which a fuel cell stack is completely assembled. Thus, when an airtightness defect occurs, the fuel cell stack is disassembled, fuel cells are separated and airtightness testing is performed thereon to locate an airtightness-defective cell.
Thus, the related art requires a great deal of time to test airtightness of a fuel cell stack, the overall testing process is complicated, and normal cells may be damaged in the process of disassembling the fuel cell stack and separating the fuel cells.
Matters described in the background art section are provided to promote understanding of the background of the present disclosure, and may include matter that is not prior art known to those skilled in the art to which the present disclosure pertains.